Raise drilling machine

ABSTRACT

A rotary drilling rig employs a drill string suspended and rotated by a power head guided for longitudinal movement within a mast mounted on a base. A power-driven spooling drum receives a cable which passes between a crown block on the mast and a travelling block supporting the power head. The mast is proportioned to absorb the reaction torque of the power head and to transmit it to the base. A first bit on the lower end of the rotary drill string forms a pilot hole in the earth as the drill string descends by gravity under control of a brake on the spooling drum as it unspools the cable. The pilot hole intersects a shaft in the earth, where a larger bit is installed on the lower of the drill string, to cut upwardly. Torque is then applied to the drum to turn it at a speed between a stalled condition and very low r.p.m. to keep a tension on the cable, thereby applying a lifting force to the rotary drill string and larger bit to enlarge the pilot hole from the bottom up.

United States Patent Charles K. Presley Primary Examiner-Emest R. PurserAttorney-Lyon & Lyon ABSTRACT: A rotary drilling rig employs a drillstring uspended and rotated by a power head guided for longitudinalmovement within a mast mounted on a base. A powerdriven spooling drumreceives a cable which passes between a crown block-on the mast and atravelling block supporting the power head The mast is proportioned toabsorbthe reaction torque of the power head and to transmit it to thebase. A first bit on the lower end of the rotary drill string forms apilot hole in the earth as the drill string descends by gravity undercontrol of a brake on the spooling drum as it unspools the cable. Thepilot hole intersects ashaft in the earth, where a larger bit isinstalled on the lower of the drill string, to cut upwardly. Torque isthen applied to the drum to turn it at a speed between a stalledcondition and very low r.p.m. to keep a tension on the cable, therebyapplying a lifting force to the rotary drill string and larger bit toenlarge the pilot hole from the bottom up.

PATENTEU AUG] 0 ran SNEET 1 OF 2 RAISE DRILLING MACHINE This inventionrelates to raise drilling and is particularly directed to improvedapparatus for drilling a pilot hole in the earth into an existing mineshaft or the'like and then using the same apparatus to enlarge the pilothole from the bottom up. Raise drilling apparatus of this general typeis disclosed in the Cannon et al.'U.S. Pat. No. 3,220,494 494 and in theWinberg U.S. Pat. No. 3,231, 029. However, the devices disclosed inthese patents apply hydraulically operated rams for raising and loweringthe rotary drill string, with the result that the length of theoperating stroke is limited by the effective length of the rams. It isan object of this invention to employ apparatus of the general type usedin the drilling of wells by the rotary method, wherein a derrick or mastsupports the drill string by means of a crown block and travelling blockhaving a cable rove between them, the cable being spooled on apowerdrive'n drum. A much longer stroke, as determined by the height ofthe mast, is thus obtained, and much greater drilling depths are madepossible.

Other and more detailed objects and advantages will appear hereinafter.

In the Drawings: FIG; 1 is a side elevation showing a preferred form ofthis invention. r

FIG. 2 is an end elevation of the device shown in FIG. 1. FIG. 3 is asectional view on an'enlarged scale, showing the upward-acting bit inplace on the lower end of the drill string for enlarging the previouslyformed pilot hole.

FIG. 4is a plan view in diagrammatic form, showing the spooling drum andthe power means for turning it.

. Referring to the drawings, the'base supports a mast 11 having a crownblock 12 at its upper end. A travelling block 13 within the mast 11 issuspended from the crown block 12 by means of a cable 14 rove betweenthe blocks and extending downward from the sheave 15 to the spoolingdrum 16, forming a part of the hoist assembly 17. Friction brake rims 18of conventional form are contacted by conventional brake bands, notshown, operated by the manual brake lever 19. The drum shaft 21 .issupported on axially spaced bearings 22. Power to rotate the drum shaftand spooling drumis supplied through sprocket 23 and air-operated clutch24. An endless chain 25 drives the sprocket 23 from the driving sprocket26.

A change speed transmission, generally designated 27 and of conventionalform, includes a driven shaft 28 to which the sprocket 26 is afiixed,and a driving shaft 29. Each shaft is supported in spaced bearings.Chain and sprocket drives 31, 32 and 33, each provided with a clutch,provide means for driving the shaft 28 at any one of three differentspeeds and for a given speed of the driving shaft 29. In addition, gears34 and 35 afford a means of driving the shaft 28 in a reverse direction,by lateral shifting of the gear 34 to bring it into mesh with the gear35.

A prime mover 37 has a sprocket 38 fixed to its power shaft 39 andarranged to drive by a chain 40 a sprocket 41 loose on the shaft 29. Aclutch 42 is shiftable laterally in one direction to connect thesprocket 41 in driving relation with the shaft 29. The sprockets 38 and41 are used for turning the spooling drum 16 at substantial speeds forhoisting operations. The prime mover 37 may take the form of a directcurrent motor of about 350 horsepower and variable speed. A much smallermotor 51 may comprise an alternating current slip clutch motor of 30horsepower. This variable speed motor 51 drives the sprocket 52 throughsprocket S3 and chain 54. The sprocket 52 is clutch connectedto theshaft 29 by lateral shifting of the clutch 42.

From this description, it will be understood that there are two powerpaths to the transmission shaft 29: (a) From large motor 37 throughsprocket 38, chain 40 and sprocket 41, and (b) From small motor 51through sprocket 53, chain 54 and sprocket 52. The first of these powerpaths through chain 40 is a high-speed drive for hoisting operations,and the second power path through chain 54 is a'low speed drive forsupplying torque to the spooling drum 16 at speeds varying from a thussuspended and rotated by means of the power head 61. A

variable speed electric motor 64 is connected to drive the power head61. This motor'64 may be an alternating current slip clutch motor or adirect current motor.

In operation, a first bit 67 of conventional design is installed in' thelower end of the section drillstring 63. The drill string 63 is rotatedby means of the power head 61 as it is lowered by gravity. The brakelever 19 is manipulated to allow the spooling drum 16 to turn ,under,tension in the cable l4.Drilling mud or air may be circulated downwardthrough the interior of the hollow drill string 63 to emerge throughholes in the bit 67 and return upward through the pilot hole 68 beingdrilled in the earth. The rotary swivel for introducing the mud or airinto the drill stream, and the apparatus for receiving the mud andcuttings from the pilot hole68, are both conventional and are omittedfrom the drawings. The torque reaction from the power head 61 is appliedto the carriage 58 and then through the rollers 57 and track 56 to themast 11. The mast is of heavy construction,.closed on three sides andopen on one side, and capable of withstanding a reaction torque of200,000 I footpounds when the travelling block is in its highestoperating position. The mast includes diagonal braces 70 to absorb thetorque transmitted to the base 10. The external braces 71 connected totheA-frame'72 on the base 10 also: serve to transfer the twisting momenton the mast 11 to the base 10.

The downward drilling operation proceeds, adding sections to the drillstring 63'as required, until the bit 67 breaks into a subterranean shaftsuch as the mine shaft 73. If the pilot hole 68 is a deep one, or ifvery hard earth formation material is encountered, it may be necessaryto change the bit 67 a number of times before the mine shaft 73 isreached. During the operation of hoistingthe drill string 63 section bysection, in order to replace the bit 67 at the surface, the hoistingdrives through chain 40 from the prime mover37 are employed.

" After the bit 67 has broken through into the mine shaft 73, it isremoved from the lower end of the drill string and a larger bit 74 isinstalled on the lower end of the drill string 63 by workmen inthe mineshaft 73. This bit 74 employs cutting rollers 75 which engage all of thefrustoconical surfaces 76 formed between the pilot hole 68 and theenlarged hole 77. As the drill string 63' is rotated by the power head61 to turn the upward acting bit 74, the cable 14 is tensioned byapplying a torque to thespooling drum 16 through'the variable speedelectric motor 51, chain 54, shaft 29 and through the lowspeed drive 31to the shaft 28. The air clutch 24 is'closed so that the sprocket 23drives the drum shaft 21 and spooling drum 16. This power path appliestorque to the drum 16 to tension the cable but turns the drum at speedsvarying from a stalled position to very low rpm. and under close speedcontrol. The pilot hole 68 is thus enlarged from the bottom up.

The raise drilling device may also be used for drilling a hole at anangle. Thus, as shown by the phantom lincs'in FIG. 1, the mast 11 may betilted around the pivot pins 79 (see FIG. I) positioned at the upperends of the parallel posts 80 fixed to the base 10, after removal of theconnecting pins 81. This tilting movement of the mast may beaccomplished by means of the pair of extensible hydraulic rams 82. Theshoes 83 at the lower end of each of the angular external braces orstruts 71 slide to a new position on the A-frame 72 and are fixed insuch new position by means of bolts 84.

For purposes of transport, the mast 11 may be lowered about the pivotpins 79 to engage the headrest 85 fixed on the base 10. The rams 82 areemployed for lowering the mast 11 into engagement with the headrest 85as well as for returning it to drilling position, either vertical orinclined.

We claim:

1. In a raise drilling rig for enlarging a hole in the earth by means ofan upward cutting bit, the combination of: a base, a mast mounted on thebase, a crown block on the mast, a travelling block within the mast, acable rove between the blocks, a carriage suspended from the travellingblock, means on the mast guiding the carriage for movementlongitudinally of the mast, a drill string extending into the hole andcarrying the upward cutting bit at its lower end, means including apower head on the carriage for suspending the drill string and forrotating it, the mast being proportioned to absorb the reaction torqueof the power head as applied to the carriage and to transmit it to saidbase, a spooling drum on the base for windingsaid cable, and variablespeed power means on the base for applying torque to the spooling drumat zero to very low rpm. to tension the cable, whereby the drill stringmay be simultaneously rotated and pulled upward to enlarge the hole.

2. The combination set forth in claim 1 in which the mast is mounted forangular adjustment on the base, for inclined drilling.

3. The combination set forth in claim 1 in which said guide meanscomprises a track within the mast engaged by rollers on the carriage.

4. The combination set forth in claim 1 in which the variable speedpower means includes an alternating current slip clutch motor.

5. The combination set forth in claim 4 in which the power head alsoincludes an alternating current slip clutch motor.

6. In a rotary rig for raise drilling, the combination of: a base, amast mounted on the base, a crown block on the mast, a travelling blockwithin the mast, a cable rove between the blocks, a carriage suspendedfrom the travelling block, means on the mast guiding the carriage formovement longitudinally of the mast, a drill string extending below thebase, means including a power head on the carriage for suspending thedrill string and for rotating it, the mast being proportioned to absorbthe reaction torque of the power head as applied to the carriage and totransmit it to said base, a spooling drum on the base for winding saidcable, power means on the base for driving the drum, said power meansincluding a prime mover and high-capacity transmission connectionsoperatively connecting the prime mover to drive the drum for hoistingthe drill string, said power means also including means for applyingtorque to the drum from a stalled position to a very low rpm. for raisedrilling, and brake means for impeding rotation of the drum, whereby thedrill string may be rotated and permitted to descend by gravity to forma hole in the earth when the drill string is supplied with downwardcutting bit, and whereby the drill string may be rotated and pulledupward to enlarge the hole when the drill string is supplied with anupward cutting bit larger than the first.

7. The combination set forth in claim 6 in which the mast is mounted forangular adjustment on the base, for inclined drilling.

8 The combination set forth in claim 6 in which said guide meanscomprises a track within the mast engaged by rollers on the carriage.

9. The combination set forth in claim 6 in which the means for applyingtorque to the drum from a stalled position to a very low r.p.m.comprises an electric motor.

1. In a raise drilling rig for enlarging a hole in the earth by means ofan upward cutting bit, the combination of: a base, a mast mounted on thebase, a crown block on the mast, a travelling block within the mast, acable rove between the blocks, a carriage suspended from the travellingblock, means on the mast guiding the carriage for movementlongitudinally of the mast, a drill string extending into the hole andcarrying the upward cutting bit at its lower end, means including apower head on the carriage for suspending the drill string and forrotating it, the mast being proportioned to absorb the reaction torqueof the power head as applied to the carriage and to transmit it to saidbase, a spooling drum on the base for winding said cable, and variablespeed power means on the base for applying torque to the spooling drumat zero to very low r.p.m. to tension the cable, whereby the drillstring may be simultaneously rotated and pulled upward to enlarge thehole.
 2. The combination set forth in claim 1 in which the mast ismounted for angular adjustment on the base, for inclined drilling. 3.The combination set forth in claim 1 in which said guide means comprisesa track within the mast engaged by rollers on the carriage.
 4. Thecombination set forth in claim 1 in which the variable speed power meansincludes an alternating current slip clutch motor.
 5. The combinationset forth in claim 4 in which the power head also includes analternating current slip clutch motor.
 6. In a rotary rig for raisedrilling, the combination of: a base, a mast mounted on the base, acrown block on the mast, a travelling block within the mast, a cablerove between the blocks, a carriage suspended from the travelling block,means on the mast guiding the carriage for movement longitudinally ofthe mast, a drill string extending below the base, means including apower head oN the carriage for suspending the drill string and forrotating it, the mast being proportioned to absorb the reaction torqueof the power head as applied to the carriage and to transmit it to saidbase, a spooling drum on the base for winding said cable, power means onthe base for driving the drum, said power means including a prime moverand high-capacity transmission connections operatively connecting theprime mover to drive the drum for hoisting the drill string, said powermeans also including means for applying torque to the drum from astalled position to a very low r.p.m. for raise drilling, and brakemeans for impeding rotation of the drum, whereby the drill string may berotated and permitted to descend by gravity to form a hole in the earthwhen the drill string is supplied with downward cutting bit, and wherebythe drill string may be rotated and pulled upward to enlarge the holewhen the drill string is supplied with an upward cutting bit larger thanthe first.
 7. The combination set forth in claim 6 in which the mast ismounted for angular adjustment on the base, for inclined drilling. 8.The combination set forth in claim 6 in which said guide means comprisesa track within the mast engaged by rollers on the carriage.
 9. Thecombination set forth in claim 6 in which the means for applying torqueto the drum from a stalled position to a very low r.p.m. comprises anelectric motor.